Answer:

Explanation:
The formula for arc length is:

Where Θ is measured in degrees.
We know that the arc length is 8π when the degree is 80. So, substitute 8π for A and 80 for Θ:

Divide both sides by 2π:

Simplify the fraction:

Multiply both sides by 9/2:

So, the radius is 18.
Now, we can find the area of the circle. The formula for the area of a circle is:

Substitute 18 into r:

Simplify:

And we're done!